Apparatus and method for fusing battery terminals with improved induction heating power control

ABSTRACT

An apparatus and method for fusing the ends of battery cell terminal posts and the ends of hollow bushings fixed in the plastic cover of a battery being assembled and within which the terminal posts are concentrically disposed. The apparatus includes a pair of induction heating coils which each concentrically support a mold cavity insert adapted to receive the ends of the terminal posts and bushings to be fused and a ferrite insert adapted to concentrate induced current in the ends of the terminal post and bushings upon energization of the coils. An electrical control is provided for selectively generating a radio-frequency oscillating current in the coils to effect heating, melting, and fusion of the ends of the terminal posts and bushings to consistent fusion depths while the plastic battery case remains substantially uneffected. The control is adapted to substantially instantaneously energize the inductance heating coils to a first power level, maintain such power level for a first predetermined period for melting the ends of the terminal posts and bushings, and then gradually decrease the power level in a substantially uniform controlled manner for a second predetermined period to produce finished fuse terminals with good surface appearance.

RELATED APPLICATION

Lund et al., U.S. application Ser. No. 533,080 filed Sept. 19, 1983 forApparatus and Method for Fusing Battery Terminals.

DESCRIPTION OF THE INVENTION

The present invention relates generally to the manufacture of lead acidstorage batteries, and more particularly, to an improved apparatus andmethod for fusing battery cell terminal posts to respective bushings inthe battery casing to form the external terminals of the completedbattery.

In the manufacture of lead acid storage batteries, it is customary toassemble the individual battery cells into a case with the terminalcells each having an upstanding lead terminal post located at opposedends of the battery, to then position a cover having cylindrical leadbushings fixed therein onto the battery case with the terminal postsextending through respective of the bushings, and to then heat, melt,fuse, mold, cool, and freeze the upper ends of the bushings and posts toform the finished battery terminals. Since the case and cover in modernday batteries commonly are made of plastic, care must be taken in fusingthe terminal posts and bushings so as not to melt or otherwise damagethe immediately adjacent portion of the cover, which can either renderthe battery defective or sufficiently weaken the seal and supportbetween the cover and bushings as to create a potentially dangerouscondition during use of the battery.

Heretofore it has been common practice to fuse the terminal posts andbushings by melting the ends thereof by means of an acetylene torchwhich is manually held and operated. Not only does such procedure failto lend itself to use in a fully automated battery production line, butthe quality and depth of the fused areas of the terminal posts andbushings vary with the operator who performs the fusion process, andeven between terminals of successive batteries fused by the sameoperator since there is no reliable means for controlling the degree offusion that is effected. Moreover, it is not easily determinable whetherminimum required fusion depths are obtained, i.e., generally consideredto be between 1/8 and 3/16 inch as measured from the top of the finishedterminal.

While various proposals have been made for automatically fusing batteryterminal posts and cover bushings by means of either acetylene torchheating, electrical resistance heating, or electrical induction heating,such proposals all have faced various drawbacks, including the inabilityto obtain reliable fusion depths within the requisite processing time,undesirable melting of the cover about the bushings, and unacceptableappearance of the finished terminals. Since lead oxides contained withinthe lead bushings tend to float to the surface during melting, undersome circumstances this has been found to result in unsightlyirregularities in the surfaces of the finished battery terminals.

It is an object of the present invention to provide an improvedapparatus and method for fusing the terminal posts and casing bushingsin forming battery terminals.

Another object is to provide an apparatus as characterized above whichpermits reliable and effective fusion of the terminal post and bushingsin a relatively short time, and thus, is adaptable for use in a fullyautomated battery production line.

A further object is to provide an apparatus of the foregoing type whichpermits quick automated fusion of the terminal posts and cover bushingswhile reliably effecting proper fusion depths of the finished terminals,preventing cover melting or damage, and obtaining completed batteryterminals with relatively good surface appearance.

Other objects and advantages of the invention will become apparent uponreading the following detailed description and upon reference to thedrawings, in which:

FIG. 1 is a perspective of a completed battery having terminals formedby the apparatus and method of the present invention;

FIG. 2 is an enlarged section of one of the fused terminals of thebattery shown in FIG. 1, taken the plane of line 2--2;

FIG. 3 is an exploded vertical section showing a cover being positionedonto a battery case during assembly of the battery;

FIG. 4 is a vertical section showing a battery with the cover assembliedon the case and the battery operatively positioned in the illustratedapparatus, prior to fusing of the terminal post and cover bushing;

FIG. 5 is a horizontal view of the top of the mold insert of theillustrated apparatus, taking in the plane of line 5--5 and FIG. 4;

FIG. 6 is a front elevational view of the illustrated terminal postfusion apparatus, taken in the plane of line 6--6 in FIG. 7;

FIG. 7 is a side elevational view of the illustrated apparatus, taken inthe plane of line 7--7 of FIG. 6;

FIG. 8 is an enlarged fragmentary section of the induction heating coilsand support of the illustrated apparatus, taken in the plane of line8--8 in FIG. 6;

FIGS. 9-11 are sections taken in the planes of lines 9--9, 10--10, and11--11 in FIG. 8 respectively;

FIG. 12 is a schematic of a down-slope heat control circuit for theinduction heating coils of the illustrated apparatus;

FIG. 13 is a graphic illustration of the heat cycle of the illustratedapparatus; and

FIG. 14 is a block diagram of the Master Controller of the illustratedapparatus.

While the invention is susceptible to various modifications andalternative constructions, a certain illustrated embodiment thereof hasbeen shown in the drawings and will be described below in detail. Itshould be understood, however, that there is no intention to limit theinvention to the specific form disclosed, but on the contrary, theintention is to cover all modifications, alternative constructions andequivalents falling within the spirit and scope of the invention. Thus,while the present invention will be described in conjunction with themanufacture of a lead-acid storage battery for starting, lighting andignition (hereinafter "SLI") applications, it will be appreciated thatthe invention is equally applicable for other battery applications.Similarly, while the invention will be described in connection with topterminal battery connections, the invention also is applicable to theconnection of other battery components, such as side terminals,intercell connectors, and the like. Moreover, it will be understood thatthe invention is applicable to devices, other than batteries, which havefusible components.

Referring now to FIG. 1, there is shown an illustrative fully assembledand processed SLI battery 10 having terminals 11 formed on the top sidethereof by a terminal fusion apparatus in accordance with the presentinvention. The illustrated battery 10, which is of a type generallysimilar to that shown in Klang et al. application Ser. No. 352,924 filedFeb. 26, 1982, includes a case 14, preferably made of plastic, formedwith a plurality of internal divider partitions 15 that form individualcompartments for containing respective battery cell elements 18I or 18T.The illustrated battery 10 includes six cell elements, namely twooutermost terminal cell elements 18T at opposed ends of the battery andfour intermediate cell elements 18I located therebetween. As is known inthe art, the electrode plates of like polarity of each battery cellelement 18I, 18T are electrically coupled together by a respective castlead lug-strap 19I or 19T. The lug-straps 19T for the terminal cellelements 18T are provided with an upstanding terminal post 20 which maybe integrally formed with the strap 19T, or alternatively, the post 20may be separately cast or otherwise mounted on the strap 19T.

During assembly of such batteries, it is customary to assemble the cellelements 18I, 18T in the case 14, either before or after the lug straps19I, 19T and terminal posts 20 are cast thereon. Prior to closing thetop of the battery, the lug straps 19I are suitably joined togetherthrough the partitions 15 (as shown in FIG. 3) and a cover 21 withterminal bushings 22 mounted therein is thereafter positioned onto thecase 14 with the terminal posts 20 extending co-axially through thebushings 22 (FIG. 4). The bushings 22 have a slight upward externaltaper, shaped according to industry standards, and a tapered axialopening 24, shaped generally complimentary to the terminal posts 20. Thelowermost end of the bushing opening 24 has an outwardly flared chamfer24a (FIG. 3) for guiding the terminal post 20 into proper seating in thebushing during assembly of the cover 21 onto the case 14. In theillustrated embodiment, the terminal posts 20 are of sufficient heightthat upon assembly on the cover 21 the tops of the posts 20 are flushwith the tops of the bushings 22 (FIG. 4). For reliably supporting thebushings 22 in the cover 21, the bushings 22 each preferably have aribbed peripheral mounting portion 25 that is adapted to provide astrong mechanical connection with the plastic cover 21 while forming aneffective seal about the periphery of the cover and bushing.

Referring now to FIGS. 6 and 7, there is shown a battery terminal fusionapparatus 30 embodying the present invention which has induction heatingmeans adapted for quickly, reliably, and automatically heating, melting,and fusing the ends of the terminal posts and cover bushings to properand consistent fusion depths with good surface appearance, while notmelting or otherwise damaging the plastic battery case and cover. Theillustrated apparatus 30 is included in an automated production linehaving a conveyer track 31 upon which batteries being assembled aremoved through successive operating stations. The track 31 is supportedon a structural frame 32 and comprises a pair of laterally spacedelongated bottom track members upon which the batteries ride. Anupstanding side-reference rail 34 is located immediately adjacent thetrack, and suitable chain conveyer means, generally indicated at 35, isprovided for moving the batteries along the tracks.

For stopping the batteries at predetermined operating stations along thetrack 31, a plurality of pivotable stops 36 are mounted on the undersideof the track. To selectively move the stops from a retracked position,shown in phantom in FIG. 6, to a raised battery stopping position shownin solid lines, the stops 36 each are pivotably mounted on respectivepivot shafts 38 and have one end coupled to a rod 39a of a respectiveair cylinder 39 fixed at its opposite end to the frame 32. Thus, asshown in FIG. 6, batteries may be successively stopped at a readystation 40 for the fusion apparatus 30 with the cover 21 mounted on thecase 14 and the terminal posts 20 extending upwardly through therespective cover bushings 22, as previously described. During the nextoperating cycle of the production line, the cylinders 39 are actuated toretract the stops 36, the batteries are advanced along the track 31 tothe succeeding operating stations, and the stops 36 are again raised byreverse actuation of the air cylinders 39, thereby successively movingbatteries from the ready station 40 to the terminal fusion apparatus 30and from the fusion apparatus to the next station. Following advancementof a battery to the terminal fusion apparatus 30, the battery is firmlypositioned against the side-reference rail 34 by actuation of a cylinder41, the rod 41a of which extends into engagement with the side of thebattery and moves it into proper position against the rail 34. Forsensing the proper position of a battery against the side-reference rail34, a limited range photosensor 42 is mounted on the opposite side ofthe rail 34 immediately adjacent an aperture 44 therein and is adaptedto sense the presence of a battery only when positioned against the siderail.

The terminal fusion apparatus 30 includes a pair of induction heatingcoils 50 disposed in an aligned relation to the terminal posts 20 andbushings 22 of a battery properly positioned at the fusion apparatus,and an elevator 51 is provided for effecting relative movement betweenthe battery and coils 50 such that the ends of the battery terminalposts and bushings are positionable in operative relation to theinduction heating coils. The elevator 51 is mounted immediately belowthe track 31 and includes a pair of upstanding legs 52 that can beselectively raised and lowered with respect to the track 31. Theelevator 51 is secured on the transverse mounting plate 54 fixed at theupper end of a rod 55a of an air cylinder 55 such that actuation of thecylinder 55 and extension of the rod 55a will lift the elevator causingthe legs 52 to be raised above the level of the track, lifting thebattery off the track and positioning terminal posts 20 and bushings 22thereof into the underside inductance heating coils 50. Reverseactuation of the air cylinder 55 lowers the elevator 51 and repositionsthe battery onto the track 31 for subsequent movement along theproduction line. To guide such elevator movement, the traverse mountingplate 54 is supported for vertical movement on upstanding guide rods 56(FIG. 6). In order to permit relatively precise adjustment of thelifting movement of the elevator 51, stops 58 are threadably mounted onupstanding bolts 59 carried by the frame 32. A magnetic switch 60 on thecylinder 55 senses the raised condition on the elevator 51, and a switch61 senses the lowered condition.

The induction heating coils 50 in this instance are supported incantilever fashion from the cabinet 65 of the induction generator of theterminal fusion apparatus 30 immediately below a protective hoodpositioned to prevent inadvertent contact with the coils 50, and arerigidly studded to a coil brace 66. For supporting the coils 50 inlongitudinally spaced relation corresponding to the spacing between thebattery terminals to be fused, the coils are carried by a T-buss 68which in turn is supported at a desired elevation by a dropper buss 69fixed to the induction output plates on the cabinet 65 of the inductiongenerator (FIGS. 7 and 8). The coils 50 preferably each comprise acontinuous length of copper tubing formed in a helix configuration ofconcentric circular turns 50a, 50b, 50c (FIGS. 4 and 10), and the coils50 are interconnected to form part of a continuous inductance heatingand cooling circuit 70a-70g (FIG. 8). Such copper tubing circuit in thisinstance includes an inlet section 70a communicating from the cabinet 65and supported by the dropper buss 69, a T-buss section 70b communicatingwith the inlet section 70a and supported by the T-buss 68, a section 70ccommunicating with the T-buss section 70b and forming one of the coils50, a section 70d communicating between the section 70c and a section70e forming the other coil 50, a T-buss section 70f communicating withthe section 70e and supported on an opposite side of the T-buss 68 asthe section 70b, and an outlet section 70g communicating between theT-buss section 70f and the cabinet 65 and supported by the dropper buss69 on the side opposite the section 70b.

The illustrated dropper buss 69 comprises a pair of copper plates 69a,69b separated by an insulating spacer 75a and fixed to the outside ofthe cabinet 65. The T-buss 68 comprises a pair of L-shaped copper plates68a, 68b separated by an insulating spacer 75b coupled together by bolts76 (FIG. 8), and mounted in an outwardly extended relation to thedropper buss 69 by bolts 78 (FIG. 9). The T-buss 68 further includes aforward plate 68c secured forwardly of the L-shaped plates 68a, 68b bybolts 79 and separated therefrom by an insulating spacer 75c. Forwardlyextending insulator spacers 75d separate inlet and outlet legs of eachcoil 50. The coils 50 in this case each are supported by an angle flange80 secured to the T-buss 68 by bolts 81 (FIG. 11). The coils 50 aresuspended from an outwardly extending horizontal flange of each angleflange 80 by depending studs 82 having inwardly angled ends 82a fixed tothe coil turns. To provide further rigidity to the cantilever coilsupport, bolts 84 in this case are connected between the underside ofthe coil brace 66 and the angle flanges 80 (FIGS. 6 and 7). It will beunderstood that suitable seals and insulating means are provided betweenthe various buss plates and copper tubing couplings so as to form acontinuous low-resistance electrical and leak-free fluid circuit throughthe copper tubing sections 70a-70g.

The input and output sections 70a and 70g of the copper tubing canthereby be electrically coupled to a high voltage, radio-frequencygenerator 90 of a known type, for example, on the order of 20 kilowattcapacity, contained within the cabinet 65 such that upon energization ofthe generator 90 (FIG. 7) current flow through the tubing circuit70a-70g induces high level heating in materials located in axialrelation to the coils 50. It will be understood that inductiongenerators of other capacities and with higher or lower frequenciescould alternatively be used. Such inductance heating has been found topermit substantially instantaneous heating of lead terminal posts 20 andbushings 22 located in operative relation to the coils 50 totemperatures in excess of 1000° F., well above the melting point oflead. For cooling the copper tubing and the generator of heat created bysuch high-frequency current effects, as is known in the art, coolingwater may be circulated through the tubing sections 70a-70g, coolinglines in the generator coupled to the tubing sections, and then througha radiator 91, in this instance mounted on the cabinet 65.

For receiving the terminal posts and cover bushings of a battery to befused and for conforming melted ends thereof to the proper configurationduring energization of the coils 50, each of the induction heating coils50 removably supports a mold insert 95 in depending fashion from theunderside thereof, each of which is formed with a mold cavity 96. Theillustrated mold inserts 95 each have a cylindrical shape and are formedwith an annular shoulder 98 (FIG. 4) positionable against the undersideof the lowermost coil turn 50a, and an annular groove 99 formed inupwardly spaced relation to the shoulder 98 for receiving a flexibleretainer washer 100, preferably made of a temperature-resistantelastomer, which enables the mold insert 95 to be captively supported bythe lowermost coil turn 50a. The cavity 96 of the mold insert 95 isshaped in substantial conformity to the bushing 22 so as to form anuppermost end of the battery terminal upon melting and fusion of theupper ends of a bushing and terminal post positioned therein. Tofacilitate seating of a bushing and terminal post into proper positionin the mold cavity 96 upon lifting of a battery from the conveyer track31 by the elevator 51, the lowermost end of the cavity 96 is formed withan outwardly flared chamfer 96a. The upperside of the mold insert 95preferably is enclosed by a relatively thin walled apertured partition101 that serves to prevent metal from contacting the coil 50 during thefusion operation, while permitting expanding gases to escape throughapertures 102.

The mold insert 95 preferably is made of Teflon which unexpectedly hasbeen found to withstand the relatively high temperatures that occurduring the fusion operation and which forms the fused terminals with arelatively smooth clean surface. Such mold inserts 95 have been found tobe adaptable for fusing 3000 or more terminals without replacement. Itwill be appreciated by one skilled in the art, however, that the inserts95 may be economically produced and are easily replaceable on a regularbasis by simply removing the flexible retainer washer 100.

For enhancing quick and reliable heating, melting and fusion of theuppermost ends of the battery terminal posts 20 and cover bushings 22positioned in the mold cavities, while not adversely effecting theportions of the plastic cover 21 immediately adjacent the bushings, thelowermost turn 50a of each coil surrounds the mold insert 95 at a pointabout midway down the bushing and terminal post cavity 96 and and thecoil turns 50b, 50c are of relatively smaller diameter, correspondingsubstantially into the diameter of the upper end of the terminal to befused, and are located in vertically spaced relation above the moldinsert 95. Such a coil arrangement has been found to concentrateinduction heating effects onto the upper ends of a bushing and terminalpost disposed in the mold cavity 96 so as to effect melting and fusionof the ends without significantly affecting the lower parts thereofadjacent that battery cover.

For further intensifying the induction heating affect of the coils 50onto the terminal post and bushing ends, a current concentrating insert105 is supported within the two uppermost coil turns 50b, 50c, as shownin FIG. 10. The insert 105 preferably is made of ferrite, or such othermetallic material which has the affect of intensifying or concentratingcurrent induced by the coil 50 in the upper ends of the bushing andterminal post located in operative relation thereto. The use of such aninduction heating coil 50 and current concentrating insert 105arrangement has been unexpectedly found to enhance heating of the leadbushing and terminal post parts such that they can be consistentlymelted to fusion depths of as much as 3/8 of an inch in less than threeseconds.

In accordance with the invention, means are provided for controlling theinduction heating cycle such that the coils 50 are instantaneouslyenergized to a predetermined full power level, are maintained at suchfull power for a predetermined relatively short period to melt thebushing and terminal post ends, and then the power level is graduallydecreased in a uniform and controlled manner for fusing the terminalswith a relatively smooth surface. In the illustrated embodiment, thepower level of the radio-frequency generator 90 is controlled by an SCRpower control 110 (FIG. 14) which in turn is activated by a MasterController 111 adapted to control the various operating functions of thefusion apparatus 30, as will become apparent. Upon positioning of theterminal posts 20 and bushings 22 of a battery into operative relationwith the induction heating coils 50, the Master Controller 111 isadapted to energize the SCR power control 110, which energizes theinduction heating generator to a full power capacity, as graphicallydepicted in FIG. 13. After a predetermined period, as timed by theMaster Controller 111, the Master Controller will shut off the supply ofpower to the SCR power control.

In order to provide a controlled power decrease to the induction heatingcoils from the full power level to a completely de-energized statefollowing the Master Controller 111 shut-off of power to the SCR powercontrol 110, a down-slope heat control circuit 112 is provided, as shownin FIGS. 12 and 14. The down-slope heat control circuit 112 is coupledto the Master Controller 111 by input terminals 114, 115, and atransformer 116 is coupled between the input terminals 114, 115 and adiode bridge 118. A filtering capacitor 119 is coupled across the bridge118 in a line 120, and a current limiting resistor 121 and a photo diode122a of a optical coupling device 122 also are coupled across the bridgein a line 124. To activate the SCR power control 110, and thus theinduction heating generator 90, the Master Controller 111 willcommunicate an output voltage (such as 110 V) to the input terminals114, 115, which is reduced by the transformer 116 to a lower AC voltage,rectified by the diode bridge 118 and filtered by the capacitor 119 toproduce a DC current flow through the photo diode 122a. Such currentflow through the photo diode 122a activates a photo transistor 122b ofthe coupling device 122 in an R-C control circuit 128, which in turnallows a reference voltage, as established by potentiometer 126 having aDC power supply 129, to be communicated to output terminals 130, 131coupling the down-slope control circuit 112 to the SCR power control110. At the same time, a capacitor 135 coupled in parallel across thepotentiometer 126 charges to the reference voltage.

Hence, when the Master Controller 111 communicates a 110 V outputbetween input terminals 115, 116 of the down-slope heat control circuit112, the full reference voltage, as established by the potentiometer126, is communicated to the SCR power control 110 to nearlyinstantaneously energize the high-frequency generator 90 to its fullpower capacity. Following the predetermined period of full powerenergization of the generator 90, as timed by the Master Controller 111,the Master Controller de-energizes the input terminals 115, 116 of thedown slope heat control circuit 112, which turns off the photo diode122a and photo transistor 122b of the optical coupling device 122.Notwithstanding such de-energization of the input terminals 115, 116 andthe photo coupling device 122, the voltage across the capacitor 135 inthe R-C control circuit 128 continues to feed the output terminals 130,131, but decays over a determined period, such as about one second, sothat the voltage to the output terminals 130, 131, and the resultingpower level of the generator controlled by the SCR power control 110,proportionally decreases in a controlled manner to zero.

It will be appreciated, therefore, that the period of full poweroperation of the induction heating generator 90 may be selectivelyeffected by the Master Controller 111, while the controlledde-energization of the generator 90 may be controlled by the design ofthe down-slope heat control circuit 112. In practice, it has been foundthat melting of the ends of battery terminal posts 20 and cover bushings22 sufficient to achieve relatively constant and reliable fusion depthsof between 1/4 and 3/8 inch can be achieved when the generator isoperated at a full power level for about 2.5 seconds, and thatunexpected good surface appearance of the fused terminals is achieved byde-energizing the induction heating coils 50 from full power to zeropower in the foregoing controlled fashion over a period of about onesecond. The terminals preferably are thereafter allowed to cool for aperiod of about eight seconds following complete de-energization of theinductance heating coils prior to removal from the mold inserts 95. As aresult, the entire fusion operation, including raising and lowering ofthe battery into the inductance heating coils 50, can be carried out bythe apparatus of the present invention well within a period of about 20seconds. It will be understood by one skilled in the art that by virtueof such short process time, the apparatus 30 lends itself to efficientutilization in an automated battery production line where the individualprocessing operations are limited to short intervals. It will beappreciated that while the illustrated down-slope heat control circuit112 provides a relatively constant decrease from full power to completede-energization of the induction heating coils, alternatively meanscould be provided for effecting a plurality of discreet relatively smallvoltage drops in the reference voltage to the SCR power control 110.

The Master Controller 111, which can be a conventionalmicroprocessor-based programmable controller such as a Gould Modicon 84Programmable Controller, can be programmed to effect the sequentialoperation of the terminal fusion apparatus 30 of the present inventionand coordinate such operation with the transfer of batteries along theconveyor track 31. As is known in the art, the Master Controller 111 cancommunicate with the apparatus 30 through conventional input and outputmodules which convert incoming signals from the various sensing devicesof the apparatus to signal levels compatible with the controller andwhich convert output signals of the controller to signal levelscompatible with the apparatus. Hence, when a battery is transferred fromthe fusion ready station 40 to the fusion apparatus 30 and strikes araised stop 38, appropriate sensing means may provide a signal to theMaster Controller 111, in response to which the cylinder 41 is actuatedto extend its rod 41a and position the battery against theside-reference rail 34, which is sensed by the photo cell 42. Inresponse thereto, the cylinder 41 is reverse actuated to withdraw therod 41a, and the cylinder 55 actuated to raise the battery so that theterminal posts 20 and cover bushings 22 are disposed in operativerelation to the respective induction heating coils 50, such raisedposition being sensed by the magnetic switch 60 on the cylinder 55. TheMaster Controller 111 may then energize the SCR power control 110through the down-slope heat control circuit 112 to energize thegenerator 90 to full power level, maintain such full power level for apredetermined period of time to effect melting of the ends of theterminal post and bushings, and following such predetermined full powerheating period, the Master Controller 111 will shut off the inputvoltage to the down-slope heat control circuit 112, which thereafterprovides a controlled de-energization of the generator 90 and inductionheating coils 50. Following a subsequent predetermined cooling period,the Master Controller 111 will cause the reverse actuation of aircylinder 55, lowering the elevator 51 and repositioning the battery onthe conveyer track 31, as sensed by the switch 61, for transfer to thesucceeding operating station, the entire cycle of operation beingeffected in a predetermined relatively short period of time.

It will be further appreciated that the fusion apparatus 30 of thepresent invention is adaptable for processing various different sizedbatteries. To this end, the T-buss 68 may be readily removed from thedropper buss 69 by removal of the mounting bolts 78 and replaced with aT-buss configuration to accommodate different terminal spacing andlocation on the battery. The lifting stroke of the elevator 51 also maybe selectively adjusted by adjustment of the stops 58. In addition, tofurther facilitate setup of the apparatus 30 for different sizedbatteries, the cabinet 65 in this case is mounted on an X-Y table 140(FIGS. 6 and 7) comprising an upper platform 141 upon which the cabinet65 is mounted for movement parallel to the track 31 through actuation ofa ball screw 142, and a lower platform 144, upon which the cabinet 65and upper platform 141 are mounted for movement transverse to the track31 by actuation of a ball screw 145. A gauge 146 is provided tofacilitate location of a cabinet in the predetermined longitudinalposition for a particular battery size, and a gauge 148 similarly isprovided to facilitate transverse location of the cabinet.

What is claimed is:
 1. An apparatus for fusing the end of a lead batterycell terminal post to the end of a hollow lead bushing fixed in thecover of a battery being assembled and within which the terminal post isconcentrically disposed comprisingan induction heating coil; meanssupporting said induction heating coil; means supporting a battery beingassembled such that a terminal post and bushing thereof are inconcentric operative relation to said induction heating coil; means forgenerating a high-frequency oscillating current in said coil to inducecurrent flow in a terminal post and bushing in operative relation tosaid coil; and means for energizing said high-frequency currentgenerating means to a predetermined first power level, maintaining saidpower level for a first predetermined period for melting the ends ofsaid terminal post and bushing by induced current flow therein, and thencontinuously decreasing said power level to zero in a controlled mannerfor a second predetermined period of time to effect the fusion of theends of the terminal post and bushing to a controlled depth said secondpredetermined period being shorter than said first predetermined period.2. The apparatus of claim 1 including control means for effectingsubstantially instantaneous energization of said current generatingmeans to said first power level.
 3. The apparatus of claim 2 in whichsaid control means includes a control circuit having capacitive means,means for selectively communicating an input voltage to said controlcircuit for charging said capacitive means to a predetermined referencevoltage and for effecting substantially instantaneous energization ofsaid current generating means to said first power level, and means forterminating said input voltage to said control circuit after said firstpredetermined period for deenergizing said current generating meansproportionately to the voltage decay of said control circuit capacitivemeans.
 4. The apparatus of claim 2 in which said control means includesa programmable controller, power control means communicating with saidcurrent generating means, and down-slope heat control circuit meanscommunicating between said programmable controller and said powercontrol means; said programmable controller being operable toselectively produce an output voltage to energize said power controlmeans through said down-slope heat control circuit means to effectsubstantially instanteous energization of said current generating meansto said first power level and maintain said first power level for saidfirst predetermined period; and said down-slope heat control circuitmeans being operable to gradually control deenergization of said currentgenerating means upon termination of said programmable controller outputvoltage after said first predetermined period.
 5. The apparatus of claim4 in which said down-slope heat control circuit means includescapacitive means which charges to a predetermined reference voltage uponcommunication of said programmable controller output voltage to saidpower control means and which provides a controlled gradually decreasingvoltage output to said power control means proportionate to the voltagedecay of said capacitive means upon terminating of said programmablecontroller output voltage after said first predetermined period.
 6. Theapparatus of claim 1 in which said energizing means decreases said powerlevel in a substantially uniform manner for a period of time equal toabout half the period said energizing means maintains said full powerlevel.
 7. A method for fusing the end of a lead battery cell terminalpost to the end of a hollow lead bushing fixed in the case of a batterybeing assembled and within which the terminal post is concentricallydisposed comprisingsupporting an induction heating coil; supporting saidbattery being assembled such that a terminal post and bushing thereofare in concentric operative relation to said induction heating coil; andenergizing said coil to a first predetermined power level for generatinga high-frequency oscillating current in said coil to induce current flowin a terminal post and bushing in operative relation to said coil,maintaining said power level for a first predetermined period formelting the ends of said terminal post and bushing by said inducedcurrent flow, and then continuously decreasing said power level to zeroin a controlled manner for a second predetermined period of time toeffect the fusion of the ends of the terminal post and bushing to acontrolled depth said second predetermined period being shorter thansaid first predetermined period.
 8. The method of claim 7 includingsubstantially instantaneously energizing on said coil to said firstpower level.
 9. The method of claim 8 including energizing said coil tosaid first power level while simultaneously charging a capacitive meansto a predetermined reference voltage, and decreasing said power level tosaid current generating means proportionate to the voltage decay of saidcapacitive means following deenergization thereof.
 10. The method ofclaim 7 including simultaneously forming the ends of said terminal postand bushing into final fused form as they are heated and melted.
 11. Themethod of claim 7 including decreasing said power level in a uniformmanner for a period of time equal to about one-half the period saidfirst power level is maintained.
 12. The method of claim 7 includingmaintaining said first power level for a period of between two and threeseconds, and gradually decreasing said power level from said firstpredetermined level to a completely deenergized state over a period ofabout one second.